1. Field of the Invention
The invention relates to a metering device for taking up, or drawing in, volume of liquid, pasty or powdered product from at least one container and then for dispensing all or part of the volume taken up, of the sort of those which comprise:
a chamber of variable volume, closed at one end by a closure member;
means for linking the chamber with the outside,
and means for controlling the variations in the volume of the chamber, making it possible to draw in or to discharge depending on whether the volume increases or decreases in volume.
Such a device may serve for taking up and dispensing a single product as a metered quantity. It is, however, beneficial for it to be possible for such a device to serve, without having to be modified substantially, for sequentially taking up several different products, mixing these products, and dispensing the mixture.
2. Description of the Related Art
U.S. Pat. No. 5,078,302 relates to an appliance for taking up metered quantities of paints of different colors, coming from different containers and for mixing the metered quantities. The containers containing the paints of different colors are mounted on a turntable making it possible, in succession, to place each container from which a sample is to be taken in line with a sample-taking station. With each container is associated a pump consisting of a piston/cylinder assembly. A valve of a specific type is provided to interact with a cylinder base and, in one position, allows the liquid to be taken up or drawn in from the container and, in another position, allows the taken-up quantity of liquid to be discharged.
Such an appliance is relatively complicated, bulky, and expensive.